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落迦

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[求助] 求助翻译文献 就剩一段了[求助放弃]

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20080526文件夹 中的  picrender.pdf 128KB


只需要正文翻译
其他表格及参考文献就不需要翻了

[ Last edited by 落迦 on 2008-6-5 at 20:28 ]
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wang17152

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下面是剩余的最后一部分，我没时间翻译了，o(∩_∩)o...

这是第五页上的最后剩余部分，希望哪位高手能帮你继续翻译完……

From the eight zeaxanthin-producing strains, DC413, DC260, DC416, and DC404 were selected for further characterization to represent phylogenetic diversity. A panel of biochemical tests using the Enterotube II system (Table 1) showed that DC413 and DC416 had the same metabolic profile. DC260 differed from these two strains in adonitol fermentation and citrate utilization, and DC404 differed from these two strains in gas production and citrate utilization.

Comparison of carotenoid synthesis gene clusters. Cosmid libraries were constructed in E. coli for the four strains selected, and yellow positive E. coli clones were obtained for each of the strains. HPLC analysis showed that the cosmid clones from DC260 and DC413 produced zeaxanthin and glucosides. The cosmid clone from DC416 producedβ-carotene andβ-cryptoxanthin intermediates in addition to zeaxanthin and glucosides, and the cosmid clone from DC404 produced only zeaxanthin and no zeaxanthin glucosides. The data suggested that the cosmid clones isolated from DC260, DC413, and DC416 contained all the genes necessary for synthesis of zeaxanthin glucosides. The cosmid clone isolated from DC404 contained the genes necessary for synthesis of zeaxanthin but lacked the crtX gene for synthesis of zeaxanthin glucosides. Since the DC404 native strain had the ability to synthesize zeaxanthin glucosides, there is most likely a crtX gene located elsewhere in the chromosome.

The yellow positive cosmid clones were sequenced, and the carotenoid synthesis gene clusters that were determined from sequence assembly are shown in Fig. 3. Consistent with the HPLC results for the cosmid clones, all the carotenoid synthesis genes for zeaxanthin glucosides (crtEXYIBZ) were present in the clusters cloned from DC260, DC413, and DC416. The DC404 gene cluster contained the crtEYIBZ genes and lacked the crtX gene. In addition, two of the clusters, those from DC413 and DC404, contained an idi gene, encoding isopentenyl pyrophosphate isomerase (7), in the isoprenoid pathway. The organization of the carotenoid synthesis gene cluster also indicated that DC404 was more distantly related to the other strains, as suggested by phylogenetic analysis. DC404 was the first zeaxanthinproducing strain described in which the crtX gene was separated from the carotenoid synthesis gene cluster. The unique organization of the DC404 carotenoid synthesis gene cluster offers advantages for heterologous production of high-value carotenoids, such as astaxanthin. The presence of the isoprenoid idi gene in the cluster should increase the carotenoid titer (see below). The absence of the crtX gene in the cluster should prevent formation of by-products, such as zeaxanthin glucosides.

Besides the diversity in genetic organization, these genes also exhibited considerable sequence diversity. Table 2 summarizes the pairwise comparison of amino acid identities for the carotenoid synthesis genes from different strains. The carotenoid synthesis genes that we cloned from the environmental Enterobacteriaceae strains exhibited on average 60 to 70% identity with each other, as well as with the corresponding genes from the Pantoea type strains. This was also the case for the isoprenoid idi gene located in the carotenoid synthesis gene cluster. The idi genes from DC404 and DC413 exhibited 70% identity with each other and 66% identity with the ORF6 protein in Pantoea agglomerans. The ORF6 protein was annotated as having an unknown function in the GenBank database (accession number M87280) and was identified in an updated annotation as a type II Idi in the Swiss-Prot database (accession number Q01335). For the strains isolated, the carotenoid synthesis genes from DC416 and DC260 were most similar to each other. Among the different carotenoid synthesis genes, the CrtI gene appeared to be the most conserved gene. Effect of type II Idi on carotenoid production in E. coli. Two types of isopentenyl pyrophosphate isomerases (Idi) have been characterized so far. The type I Idi from various organisms, including E. coli (7), Saccharomyces cerevisiae (2), and Arabidopsis thaliana (3), requires only divalent metals for activity. In contrast, the nonhomologous type II Idi recently found in Streptomyces (9) and Bacillus subtilis (16) requires flavin mononucleotide, NAD(P)H, and divalent metal ions. The idi genes in some native carotenoid-producing organisms (Phaffia rhodozyma and Hematococcus pluvialis) exhibit homology with the type I idi genes (8). The idi genes identified in the carotenoid synthesis gene clusters from DC413 and DC404 exhibit homology with the type II idi genes. Although insertion of the isoprenoid idi gene into the carotenoid synthesis gene cluster was observed previously in P. agglomerans, many of the crtEXYIBZ gene clusters in Pantoea species (GenBank accession numbers AY166713, D90087, AB076662, and M90698), as well as the clusters from DC260 and DC416, do not contain the idi gene. The idi insertion into the carotenoid synthesis gene cluster might have occurred through a rare event during evolution. Idi catalyzes the isomerization reaction between IPP and DMAPP, which are needed in equal amounts as substrates for the first step of chain elongation (Fig. 2). This reaction was identified as one of the rate-limiting steps for isoprenoid synthesis. An increase in the enzymatic activity of this reaction by overexpression of idi could relieve this bottleneck. It has been reported that engineering the E. coli native type I idi (1, 19) or expression of an exogenous type I idi (8) could enhance production
of carotenoids in E. coli. We compared the four different gene clusters to assess the effect of the type II idi gene on carotenoid production in E. coli (Fig. 4). Four plasmids were constructed from the clusters (Table 3) by expression of all of the genes transcribed in the same orientation. These plasmids, which lacked the crtZ gene transcribed in the opposite orientation, producedβ-carotene almost exclusively in E. coli, which facilitated measurement of simple carotenoid titers by condensation of multiple peaks of zeaxanthin and glucosides into a singleβ-carotene peak. Plasmids pDCQ330 and pDCQ332 expressing the idi-containing gene clusters in E. coli showed high carotenoid titers, approximately 1,500 to 1,800 ppm. Plasmids pDCQ329 and pDCQ331 expressing the gene clusters lacking idi in E. coli showed low carotenoid titers, approximately 150 to 400 ppm. The pigmentation of the colonies also agreed with the titer measurement. The E. coli strains containing pDCQ330 or pDCQ332 were bright yellow, whereas the E. coli strains containing pDCQ329 or pDCQ331 were pale yellow. However, it is interesting that the color of the native host did not correlate with the presence of idi in the gene cluster. For example, DC404 was a lighter yellow than most of the other isolates, although the idi-containing plasmid pDCQ330 derived from DC404 gave the strongest yellow color in E. coli. Differences in host background and carotenoid regulation most likely accounted for the difference in color of the native strains.

To rule out the possibility that the higher-titer E. coli strains with the idi-containing clusters were due to higher activities of the associated crtEXYIB genes, we compared the same crtEYIB genes with and without idi. Plasmids pDCQ350 and pDCQ380 were constructed from the crtEYIB genes from DC413. An E. coli strain with plasmid pDCQ350 lacking idi yielded β-carotene at a level of 536±69 ppm, and an E. coli strain with the idi-containing plasmid pDCQ380 yieldedβ-carotene at a level of 2,655±20 ppm. This confirmed that the type II idi associated with the crtEXYIB gene cluster could increase the carotenoid titer approximately fivefold in E. coli. The higher titer obtained with pDCQ380 than with pDCQ332 might have been due to more efficient expression of the gene cluster after removal of the crtX gene.
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wang17152

木虫 (知名作家)

翻了第一页，有些太长，最近时间不多，尽量吧

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落迦(金币+25,VIP+0):很不容易了,谢谢
Diversity of Carotenoid Synthesis Gene Clusters from Environmental Enterobacteriaceae Strains

环境中肠杆菌株的类胡萝卜素综合基因簇的多样性

Eight Enterobacteriaceae strains that produce zeaxanthin and derivatives of this compound were isolated from a variety of environmental samples. Phylogenetic analysis showed that these strains grouped with different clusters of Erwinia type strains. Four strains representing the phylogenetic diversity were chosen for further characterization, which revealed their genetic diversity as well as their biochemical diversity. The carotenoid synthesis gene clusters cloned from the four strains had three different gene organizations. Two of the gene clusters, those from strains DC416 and DC260, had the classical organization crtEXYIBZ; the gene cluster from DC413 had the rare organization crtE-idi-XYIBZ;

这种生产玉米黄质素和衍生物的八类肠杆菌菌株与很多其他环境样品不同。种系发育分析表明，这些菌株与不同的欧文氏菌型菌株的组合在一起，。 对四类可以表征种系发育多样性的菌株进一步研究表明，与其生化多样性一样，它们也具有遗传多样性。类胡萝卜素的合成基因簇是由含有三种不同基因组织的四类菌株中克隆来的。两个基因簇，来自DC416菌株和DC260菌株的两个基因簇，有典型的crtEXYIBZ 组织；而DC413饿基因簇有罕见的crtE-idi-XYIBZ组织；

and the gene cluster from DC404 had the unique organization crtE-idi-YIBZ. Besides the diversity in genetic organization, these genes also exhibited considerable sequence diversity. On average, they exhibited 60 to 70% identity with each other, as well as with the corresponding genes of the Pantoea type strains. The four different clusters were individually expressed in Escherichia coli, and the two idi-containing clusters gave more than fivefold-higher carotenoid titers than the two clusters lacking idi. Expression of the crtEYIB genes with and without idi confirmed the effect of increasing carotenoid titer by the type II idi gene linked with the carotenoid synthesis gene clusters.

DC404中的基因簇含有独特的crtE-idi-YIBZ组织。除了在遗传组织的多样性，这些基因也表现相当的序列多样性。平均而言，他们存在了60%至70％共同点，与泛型菌株相应的基因一致。四个不同的集群在大肠杆菌中分别的表达，，含有idi的两类集群的胡萝卜素含量要比不含有idi的类群多出五倍以上。通过研究第二类idi基因以及类胡萝卜素的综合基因簇，考察crtEYIB基因的存在与否对胡萝卜素浓度增加的影响。

The carotenoids represent one of the most widely distributed and structurally diverse classes of natural pigments, producing light yellow to orange to deep red colors. Eye-catching examples include lycopene from tomatoes, _-carotene from carrots, and lutein from marigolds. In addition to synthesis in photosynthetic organisms, carotenoids are also synthesized in some bacteria and fungi (15). These pigments have important functions in photosynthesis, nutrition, and protection against photooxidative damage. Many studies have reported health benefits of carotenoids, including prevention of cancer (5), enhancement of immune responses (20), and improvement of visual function (6, 11). Currently, carotenoids are used as nutritional supplements, pharmaceuticals, food colorants, and animal feed additives.

类胡萝卜素是广泛分布和结构不同类别的天然色素之一，有浅黄色，橙色及深红色的色彩。比较常见的比如番茄中的茄红素， 胡萝卜中的胡萝卜素，万寿菊中的叶黄素。此外，生物光合作用及一些细菌和真菌中合成的的类胡萝卜素。这些色素在光合作用、营养和避免光照损害中具有重要的职能。有许多研究报告类胡萝卜素对健康有益，，包括防癌，加强免疫能力，改善视觉功能。目前，类胡萝卜素在医药，食品着色剂，和动物饲料添加剂领域中被用来作为营养补充品。

Most naturally occurring carotenoids are hydrophobic tetraterpenoids containing a C40 methyl-branched hydrocarbon backbone derived from successive condensation of eight C5 isoprene units. The C5 isoprene unit, isopentenyl pyrophosphate (IPP), can be generated from an acetyl coenzyme A precursor by the mevalonate pathway (21) or from the pyruvate and glyceraldehyde-3-phosphate precursors by the nonmevalonate pathway (14).

通常见到的类胡萝卜素是疏水基团是来自C40甲基骨架结构连续缩合的八个C5-异戊二烯单位。戊烯基焦磷酸（IPP）中的C5-异戊二烯单位，，可以由乙酰辅酶A的甲戊二羟酸途径中或丙酮酸和3 -磷酸甘油的非甲戊二羟酸途径中产生的前体合成出。
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落迦

银虫 (小有名气)
除去那些表格及下面的注解应该还好,    谢谢了,翻译完再让BZ帮忙转移50个JB吧,

这两天都翻这些讨厌的的文献了
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3楼2008-05-27 11:05:26
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wang17152

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用了一下午，还是没翻译完，就差倒数第二页了

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落迦(金币+35,VIP+0):稍有不通,还是谢谢了,后面的也麻烦了
IPP is isomerized to dimethylallyl pyrophosphate (DMAPP) by IPP isomerase encoded by the idi gene. IPP is then condensed with DMAPP to form the C10 compound geranyl pyrophosphate and elongated to the C15 compound farnesyl pyrophosphate (FPP). FPP is present in both carotenogenic and noncarotenogenic bacteria. The carotenogenic pathway to extend FPP to common C40 carotenoids, such as β-carotene, includes geranylgeranyl pyrophosphate synthase(CrtE), phytoene synthase (CrtB), phytoene dehydrogenase (CrtI), and lycopene cyclase (CrtY). Sometimes additional enzymes, includingβ-carotene ketolases (CrtW), β-carotene hydroxylases (CrtZ), and zeaxanthin glycosylases (CrtX), carry out subsequent modifications of β-carotene to generate a variety of C40 carotenoids.

由于二甲基丙烯焦磷酸酯(DMAPP)中的以idi基因编码的IPP异构酶的作用，异戊烯焦磷酸（IPP）是异构化的。浓缩的IPP与DMAPP反应生成名为香叶基焦磷酸的C10化合物和名为焦磷酸法呢酯(FPP)的C15化合物。FTT同时存在于可生成胡萝卜素和不可生成胡萝卜素的细菌中。胡萝卜素生成途径可将FPP延长为C40的类胡萝卜素和noncarotenogenic细菌。该carotenogenic通路延长fpp共同c40类胡萝卜素，如β -胡萝卜素，包括牻牛儿基牻牛儿基焦磷酸合成酶(CrtE)，八氢蕃茄红素合成酶(CrtB)，八氢蕃茄红素脱氢酶(CrtI),，和番茄红素环化酶(CrtY)。另外还有一些酶，包括β -胡萝卜素酮醇酶(CrtW),， β -胡萝卜素羟化酶(CrtZ)，和玉米黄质糖基(CrtX)，后面的这些β -胡萝卜素可以生成大量的的C40的类胡萝卜素。


Multiple carotenoid synthesis gene clusters have been isolated for Erwinia species (now classified as Pantoea species). Most of these gene clusters (GenBank accession numbers AY166713, D90087, AB076662, and M90698) have the classic gene organization crtEXYIBZ, with the crtEXYIB genes transcribed as an operon and the crtZ gene transcribed in the opposite orientation. In a rare gene cluster from Pantoea agglomerans (GenBank accession number M87280), an unknown gene (ORF6) is present between the crtE and crtX genes. We cloned several new carotenoid synthesis gene clusters from environmental Enterobacteriaceae strains. We discovered more diversity in the carotenoid synthesis gene clusters and demonstrated the function of the unknown gene (identified as idi), which increases the carotenoid titer.

多种多样的类胡萝卜素的合成基因簇已被隔离成为欧文氏菌种类（现已列为泛种）。大部分这些基因簇（GenBank登录加入号码有AY166713，D90087，AB076662， M90698）有标准的crtEXYIBZ分类，crtEXYIB基因作为操纵子进行转录，同时crtZ基因在相反的方向转录。对于成团泛菌（GenBank登录号m87280）的某些稀有基因簇 ，一个未知的基因(ORF6)存在于crtE和crtX基因之间。我们从环境肠杆菌株克隆了几个新的类胡萝卜素的合成基因簇。我们在类胡萝卜素的合成基因簇的那些未知的基因所表现出的功能（定义为idi基因）中发现更多的多样性，这些未知的基因增加了类胡萝卜素的浓度。

MATERIALS AND METHODS
Strain isolation. A variety of environmental samples were collected, and eight yellow-pigmented strains were isolated for growth on Luria-Bertani (LB) plates at 30°C. DC404 was isolated from soil collected from a residential garden in Wilmington, Del.; DC409, DC413, and DC414 were isolated from a Florida soil sample; DC416 and DC519 were isolated from tree bark collected in Florida; DC260 was isolated from the surface of a brick on a west-facing wall in a suburb of Wilmington, Del.; and DC266 was isolated from elm tree bark collected in Wilmington, Del. Samples were resuspended and streaked at least twice on LB plates to homogeneity. The 16S rRNA genes of the strains were amplified and sequenced as described previously (4). Fatty acid profiles of a subset of the strains were determined by gas chromatography by Microbial ID, Inc. (Newark, Del.). Biochemical tests were also performed on the strains by Microbial ID, Inc.,using the Enterotube II system (Becton Dickinson, Cockeysville, MD).

材料与方法
过滤分离。收集不同的环境样品，30℃条件下在LB碟子中培育八株黄色色素的菌株。DC404从在威尔明顿，特拉华的一个住宅花园的土壤中分离收集到的; DC409，DC413和DC414是从佛罗里达州的土壤样品中分离出来的; DC416和DC519是从佛罗里达州的树皮收集到的; DC260是威尔明顿郊区的朝西墙上的一块砖上分离下来，DC266是从威尔明顿.特拉华的榆树树皮上分离下来的。这些样本要至少两次同时放在LB 碟中。前面所述,菌株的16SrRNA基因的要扩增，排序。通过气相色谱微生物测序仪(Newark, Del.)测定某些菌株的不饱和脂肪酸的概况。使用微生物测序仪的II进气管系统对菌株做生化试验，（贝克顿迪金森， cockeysville ，医学博士）


To determine the β-carotene titers, parts of the overnight cultures were used to measure dry cell weight and parts were used to measure carotenoids. Authentic β-carotene from Sigma (St. Louis, MO) was used to construct a standard curve for carotenoid measurement. Zeaxanthin andβ-cryptoxanthin standards were purchased from CaroteNature (Lupsingen, Switzerland) for pigment identification.

测定β -胡萝卜素的浓度，部分隔夜栽培饿菌株被用来测定干细胞的重量，另一部分被用来测定类胡萝卜素含量。产自西格玛(St. Louis, MO)的已知浓度的β -胡萝卜素用来为类胡萝卜素的测量绘制标准曲线。用于色素标识的玉米黄质和β -隐黄质购买自CaroteNature （Lupsingen，瑞士）。


Cosmid library construction. A cosmid library of each strain was constructed using a pWEB cosmid cloning kit from Epicenter Technologies (Madison, WI). Genomic DNA was sheared by passing it through a syringe needle. The sheared DNA was end repaired and size selected on a low-melting-point agarose gel. DNA fragments that were approximately 40 kb were purified and ligated into the blunt-ended pWEB cosmid vector. The library was packaged using ultra-highefficiency MaxPlax lambda packaging extracts and titrated with E. coli EPI100 cells. Approximately 600 cosmid clones were grown in LB with 100 µg/ml ampicillin and screened by color. A positive yellow cosmid clone was sequenced using an EZ-TN kit (Epicenter Technologies). The sequences were assembled with the Sequencher program (Gene Codes Corp., Ann Arbor, MI).

粘粒程序库的结构。每个菌株的粘粒程序库是以震中技术(Madison, WI)中的pWEB菌株克隆方式构成的。用注射针头将DNA基因组剪切。被剪切的DNA在低熔点琼脂糖凝胶中的结束修复和选定尺寸。将大约40kb的DNA片段纯化后倒入端点平滑的pWEB粘粒载体中。使用超高效的MaxPlax λ粒子提取后将程序库包裹在一起，再与大肠杆菌的EPI100细胞测定含量。通过辨别颜色，在浓度为100 μg /ml的氨苄青霉素的LB中大约繁殖了600粘粒。使用EZ-TN（震中技术）测定阳性的黄色粘粒繁殖体 。该测定要与Sequencher程序（基因代码公司，Ann Arbor，MI）联用。


Cloning of β-carotene synthesis gene clusters. Four β-carotene synthesis plasmids (pDCQ329, pDCQ330, pDCQ331, and pDCQ332) were constructed by amplifying the carotenoid synthesis gene clusters without the crtZ gene from four strains, DC260, DC404, DC416, and DC413. The PCR fragments containing the β-carotene synthesis genes were cloned into the Eco RI site of the pBHR1 vector (MoBiTec GmbH, Goettingen, Germany). Two other β-carotene synthesis plasmids (pDCQ350 and pDCQ380) were also constructed in pBHR1 by SOEing (gene splicing by overlapping extension) PCR of the genes from the DC413 gene cluster. Plasmid pDCQ350 contained the crtE gene linked with the crtYIB genes from DC413, and plasmid pDCQ380 contained the crtE and idi genes linked with the crtYIB genes from DC413.

β-胡萝卜素合成基因簇的克隆。 4种β-胡萝卜素的合成质粒（pDCQ329，pDCQ330,，pDCQ331，和pDCQ332）是由四类不含有crtZ的类胡萝卜素（DC260, DC404, DC416, and DC413）的合成基因簇构成的。β -胡萝卜素的合成基因中聚合酶链反应的扩增片段被克隆到pBHR1媒介的EcoRI位置的（MoBiTec GmbH, Goettingen, Germany）。其他两个β -胡萝卜素的合成质粒（ pdcq350和pdcq380 ）也通过基因剪接将DC413基因的聚合酶链反应基因安置在pBHR1位置。载有crtE基因的pDCQ350质粒与来自DC413的crtTIB基因连接在一起，含有crtE和idi基因的pDCQ380质粒与来自DC413的crtYIB基因连接在一起。


Nucleotide sequence accession numbers. The nucleotide sequences of the carotenoid synthesis gene clusters isolated from DC260, DC404, DC416, and DC413 have been deposited in the GenBank database under accession numbers DQ090833 to DQ090836.

核苷酸序列编号。从DC260，DC404，DC416和DC413中分离出来的类胡萝卜素合成基因簇的核苷酸序列已被存放在GenBank数据库中，编号从dq090833到dq090836 。


RESULTS AND DISCUSSION
Isolation of pigmented strains from the environment. Eight yellow-pigmented strains were isolated from a variety of environmental samples. Both 16S rRNA gene analysis and fatty acid profile analysis indicated that these strains belong to the family Enterobacteriaceae. The 16S rRNA genes of these strains exhibited more than 97% identity to the 16S rRNA gene sequences of Enterobacteriaceae strains, including Pantoea strains, which are known to produce zeaxanthin and derivatives of this compound. A phylogenetic analysis of 16S rRNA gene sequences of these strains and several Pantoea type strains was performed. The phylogenetic tree (Fig. 1) showed that DC260, DC413, and DC414 were closely related to cluster I of Pantoea species (10), DC409, DC416, and DC519 were closely related to cluster II of Pantoea species, and DC266 and DC404 were more distantly related and grouped neither with the cluster I Pantoea species nor with the cluster II Pantoea species.

结果与讨论
从环境分离含色素的菌株。 八类来自不同的环境样本的黄色色素菌株被分离。16S rRNA基因分析及不饱和脂肪酸的资料分析表明，这些菌株属于家庭肠杆菌。这些菌株的16SrRNA基因与肠杆菌株系列的16S rRNA基因有97％以上的相同序列，包括泛株，一类众所周知的生产玉米黄质和衍生物的化合物。分析这些菌株的16S rRNA基因和某些泛型菌株的序列（图1）后发现，第一组泛物种DC260，DC413，DC414和第二组泛物种DC409，DC416，DC519密切相关，DC266和DC404与第一组和第二组中的所有物种都没联系。


High-performance liquid chromatography (HPLC) analysis of the pigments indicated that all eight strains produced zeaxanthin, β-cryptoxanthin, and β-carotene based on a comparison with authentic standards. Mass spectrometry analysis confirmed that the molecular weight (MH+) of the zeaxanthin peak was 569, the molecular weight of theβ-cryptoxanthin peak was 553, and the molecular weight of theβ-carotene peak was 537. The peaks that eluted earlier than zeaxanthin were likely zeaxanthin derivatives (e.g., zeaxanthin monoglucoside and zeaxanthin diglucoside), as suggested by liquid chromatography-mass spectrometry. A biochemical pathway for synthesis of zeaxanthin and derivatives of this compound in these Enterobacteriaceae strains is proposed in Fig. 2. The non mevalonate pathway from pyruvate and glyceraldehyde-3-phosphate precursors was proposed for IPP synthesis in these Enterobacteriaceae strains since the nonmevalonate pathway was reported previously for the closely related Erwinia strains (13).

在标准比较的基础上，高效液相色谱法（HPLC）对示踪颜色的分析表明，八类菌株都生成了玉米黄质，β -隐黄质和β-胡萝卜素。质谱分析证实，玉米黄质的分子量(MH+)高峰期是569 ，β-隐黄质的分子量高峰期是553 ，β-胡萝卜素的分子量高峰期是537 。比玉米黄质早洗脱出来的高峰可能是玉米黄质衍生物（例如，玉米黄质葡萄糖苷和玉米黄质二（葡）糖苷），与液相色谱-质谱测出的一致。 表2中提出了在这些肠杆菌株的玉米黄质的合成生化途径和这类化合物的衍生。自从甲戊二羟酸合成途径被报道与欧文氏菌菌株密切相关，合成丙酮酸和3-磷酸甘油中间体所用的甲戊二羟酸合成途径被提出用于肠杆菌株IPP的合成上。（13）
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